Coating and developing apparatus, coating film forming method, and storage medium storing program for performing the method

ABSTRACT

Disclosed is a technique for preventing a water-repellent protective film formed on a resist film from peeling off during immersion exposure. A resist film is formed on the front surface of a substrate and then the peripheral edge portion of the resist film is removed. Before forming a water-repellent protective film onto the resist film, an adhesion-improving fluid, preferably hexamethyldisilazane gas, for improving the adhesion of the water-repellent protective film, is supplied to the region from which the resist film is removed.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a technique for forming a resist filmand a water-repellent protective film on a substrate to be subjected toimmersion exposure.

BACKGROUND ART

In a photoresist process which is one of processes of manufacturing asemiconductor device, a resist solution is applied to the surface of asemiconductor wafer to form a resist film, and the resist film isexposed for the transfer of a predetermined pattern and thereafter isdeveloped, thereby to form a resist pattern. A series of these processesare generally performed using a system comprising a coating anddeveloping apparatus for the application of resist and development andan exposure apparatus connected thereto.

To meet the recent demand for miniturization of device patterns, therehas been proposed an exposure technique called immersion exposure forthe purpose of enhancing the resolution of exposure. The immersionexposure is an exposure technique wherein, in a state in which a lighttransmitting liquid layer such as a ultra-pure water layer is formed onthe surface of a wafer, light emitted from a light source is allowed topass through the liquid layer and to irradiate the wafer surface withthe light. The immersion exposure attains exposure of a high resolutionby utilizing the effect that the wavelength of light in water becomesshorter than that in the air. For example, in a case where an exposurelight source is ArF, the wavelength of ArF light in the air is 183 nm,while it is 134 nm in water. The immersion exposure technique isdescribed in Japanese Patent Laid-Open Publication JP2005-294520A (thecorresponding European patent laid-open publication: EP1732108A1), forexample.

With reference to FIGS. 14 to 17, a description will now be given aboutan immersion exposure process and related problems. Before being loadedinto a coating and developing apparatus, thin films of various materials(not shown for simplification of the drawings) are already formed on asilicon wafer W to be subjected to immersion exposure. In the coatingand developing apparatus, an antireflection film 15, a resist film 16and a protective film 17 are further formed on the wafer W in thatorder. The protective film 17 is a light-transmitting, water-repellant,thin film formed of an organic material, especially a fluorine-basedmaterial to protect the resist film 16 from the liquid used in immersionexposure.

When loaded into an exposure apparatus, the wafer W is placed on anexposure stage (not shown) and is held in a horizontal attitude. Animmersion exposure head 1 is disposed above the wafer W through a slightgap between it and the wafer. A lens 10 is disposed the center of thefront end of the immersion exposure head 1. Provided outside the lens 10are a supply port 11 for supplying a liquid, e.g., pure water to thesurface of the wafer W and a suction port 12 for sucking and recoveringthe pure water supplied to the wafer W. By supplying pure water to thesurface of the wafer W from the supply port 11 and recovering the purewater from the suction port 12, a liquid layer 18 of pure water isformed between the lens 10 and the surface of the wafer W. Light emittedfrom a light source (not shown) passes through both lens 10 and liquidlayer 18 to irradiate the wafer W with the light, whereby apredetermined circuit pattern is transferred to the resist film 16.

Subsequently, with the liquid layer 18 left present between the lens 10and the surface of the wafer W, as shown in FIG. 15, the immersionexposure head 1 is moved to a position corresponding to the nexttransfer region (shot region) and the next exposure is performed. Byrepeating this operation, circuit patterns are transferred one afteranother onto the surface of the wafer W.

As known, a device is not formed in the peripheral edge area of thewafer and the outermost peripheral portion in the peripheral edge areais a beveled portion (slant portion). For the purpose of preventing thegeneration of particles or the like, the peripheral edge portions of theantireflection film 15 and that of the resist film 16 are removed bycleaning processes using a solvent after formation of both films,respectively. Consequently, as shown in FIG. 16, a step may be formedbetween the peripheral edge of the antireflection film 15 and that ofthe resist film 16. Also, as the foregoing various thin films (notshown) formed on the wafer W before being loaded into the coating anddeveloping apparatus have been subjected to peripheral edge removingprocesses after film forming processes, respectively, the peripheraledge portions of those various thin films are also in a similar state tothe antireflection film 15 and resist film 16. Accordingly, after theperipheral edge removing process for the resist film 16, the surface ofthe wafer W, i.e., a silicon surface 1A, is exposed in the peripheraledge area of the wafer. As a result, there exist portions where theprotective film 17 is formed directly on the silicon surface 1A.

Since the protective film 17 is formed of an organic material asmentioned above, the adhesion of the protective film 17 to the siliconsurface 1A is lower than that to the resist film formed of an organicmaterial. Since the immersion exposure head 1 moves in some cases at ahigh speed of about 500 mm/sec during exposure, when the immersionexposure head 1 moves from the peripheral edge portion of the wafer Wtoward the central part together with the liquid layer 18, theprotective film 17 may possibly peel off from the silicon surface 1A dueto pressure from the liquid layer 18, as shown in FIG. 16( b). Moreover,in the stepped portion between the antireflection film 15 and the resistfilm 16, the adhesion of the protective film 17 may be low due to thecomplicated surface shape of the portion. Also in this case, due tomovement of the immersion exposure head 1 together with the liquid layer18, the protective film 17 may peel off near the stepped portion, asshown in FIG. 16( c). As a result, the edge portion of the resist film16 may be exposed without being covered with the protective film 17 andpeel off under the pressure of pure water which results from themovement of the immersion exposure head 1 together with the liquid layer18. In this case, it may be impossible to carry out a normal developingprocess.

As shown in FIGS. 16( b) and 16(c), if the protective film 17 and theresist film 16 peel off from the wafer W, the peeled resist film 16 andprotective film 17 become particles 19. The particles 19 may adhere tothe lens 10 of the exposure head 1 to obstruct a normal exposureprocess, or may again adhere to the wafer W to adversely affect theresults of various treatments after exposure of the wafer W. Theparticles 19 may be scattered onto an exposure stage for placing thewafer W thereon, adhere to the succeeding wafers W, and adversely affectthe treatment for those wafers. Such problems and solutions thereto arenot described in JP 2005-294520A.

In some cases, in order to improve the adhesion of the resist film 16 tothe surface of the wafer W, HMDS (hexamethyldisilazane) gas is suppliedto the whole surface of the wafer W after formation of theantireflection film 15 and before formation of the resist film 16 toperform a hydrophobizing process (AD process) to the surface of thewafer W. This hydrophobizing process may possibly enhance the adhesionof the protective film 17 to the silicon surface 1A. However, if theformation of the resist film 16 and the removal of the resist film 16 inthe peripheral edge portion of the wafer are performed after thehydrophobizing process, the effect of the hydrophobizing process on thesilicon surface 1A is considerably deteriorated. Thus, it may beimpossible to ensure sufficient adhesion between the silicon surface 1Aand the protective film 17 even if such a hydrophobizing process isperformed.

DISCLOSURE OF THE INVENTION

The present invention has been accomplished for solving theabove-mentioned problems and it is an object of the invention to providea technique for enhancing the adhesion of a protective film of awater-repellent material applied to a substrate before an immersionexposure process.

In order to achieve the objective, according to a first aspect of thepresent invention, there is provided a coating and developing apparatushaving a resist film forming unit that applies a resist solution to afront surface of a substrate to form a resist film, and a developingunit that develops the resist film having been subjected to immersionexposure, the coating and developing apparatus including: a firstperipheral edge cleaner that supplies a solvent to the resist filmpresent in a peripheral edge portion of the substrate thereby to removethe same; a protective film forming unit that supplies a coatingsolution onto the resist film thereby to form a water-repellentprotective film that protects the resist film from a liquid whenperforming the immersion exposure; and an adhesion-improving processorhaving an adhesion-improving fluid feeder that supplies anadhesion-improving fluid to an exposed surface before forming theprotective film for improving adhesion of the protective film to theexposed surface, wherein the exposed surface is a surface exposed due toremoval of the resist film from the peripheral portion. A non-limitativebut most preferred example of the adhesion-improving fluid ishexamethylsilazane.

In one preferred embodiment, the adhesion-improving fluid feeder isconfigured to feed the adhesion-improving fluid also to a peripheraledge portion of a back surface of the substrate. In one preferredembodiment, the coating and developing apparatus further includes: anantireflection film forming unit that supplies a coating solution to thesubstrate before forming the resist film thereby to form anantireflection film on the front surface of the substrate; and a secondperipheral edge cleaner that supplies a solvent to the antireflectionfilm in the peripheral edge portion of the substrate before forming theresist film thereby to remove the antireflection film from theperipheral edge portion of the substrate.

In one preferred embodiment, the adhesion-improving processor furtherhas a rotary stage configured to rotate about a vertical axis whileholding the substrate horizontally; and the adhesion-improving fluidfeeder has: a first adhesion-improving fluid supply nozzle adapted tolocate above the peripheral edge portion of the front surface of thesubstrate held on the rotary stage; a second adhesion-improving fluidsupply nozzle adapted to locate below a peripheral edge portion of aback surface of the substrate held on the rotary stage; and a suctionnozzle adapted to suck the adhesion-improving fluid supplied to thesubstrate. In this case, preferably, the adhesion-improving fluid feederhas a square bracket-shaped or U-shaped nozzle body, which is arrangedso as to allow the peripheral edge portion of the substrate held on therotary stage to be inserted in the nozzle body; and the first and secondadhesion-improving fluid supply nozzles and the suction nozzle areprovided at the nozzle body.

In one preferred embodiment, the protective film forming unit has arotary stage capable of rotating about a vertical axis while holding thesubstrate, and a nozzle that supplies a coating solution for forming aprotective film to the substrate held on the rotary stage, and theadhesion-improving processor is installed within the protective filmforming unit and the rotary stage in the protective film forming unit isused as the rotary stage in the adhesion-improving processor.

In one preferred embodiment, the adhesion-improving processor furtherhas: a processing vessel; a first gas feeder, serving as theadhesion-improving fluid feeder, that supplies a gas as theadhesion-improving fluid; a stage disposed in the processing vessel forplacing the substrate thereon; and an exhaust system that exhausts aninterior of the processing vessel. In this case, in one preferred mode,the stage is shaped and sized such that the peripheral edge portion ofthe substrate projects outward from the stage when the substrate isplaced on the stage; and the adhesion-improving fluid feeder isconfigured to supply a gas as the adhesion-improving fluid to theperipheral edge portion of the front surface of the substrate placed onthe stage and to the peripheral edge portion of the back surface of thesubstrate. Preferably, the exhaust system is provided such that the gasas the adhesion-improving fluid supplied onto the substrate flows towardoutside of the substrate.

In another preferred embodiment, the adhesion-improving fluid feeder isdisposed so as to face the peripheral edge portion of the substrateplaced on the stage; and the adhesion-improving processor further has asecond gas feeder, disposed so as to face a center portion of thesubstrate placed on the stage, that supplies a purge gas toward thecenter portion of the substrate thereby to form a flow of the purge gasflowing toward outside of the substrate.

According to a second aspect of the present invention there is provideda method of forming at least a resist film and a water-repellentprotective film on a substrate to be subjected to immersion exposure,the method including the steps of: applying a resist solution to a frontsurface of the substrate thereby forming a resist film; removing theresist film existing in a peripheral edge portion of the front surfaceof the substrate by using a solvent; supplying an exposed surface,exposed due to removal of the resist film, with an adhesion-improvingfluid for improving adhesion of the protective film to the exposedsurface; and thereafter applying a coating solution for forming theprotective film to the front surface of the substrate thereby formingthe protective film.

In one preferred embodiment, in the step of supplying theadhesion-improving fluid, the adhesion-improving fluid is supplied alsoto a peripheral edge portion of a back surface of the substrate. In onepreferred embodiment, the method further includes the steps of:supplying, before the step of applying the resist solution, a coatingsolution for forming an antireflection film to the front surface of thesubstrate thereby forming the antireflection film; and removing theantireflection film existing in the peripheral edge portion of the frontsurface of the substrate by using a solvent, wherein, after the resistfilm removing step, a peripheral edge of the resist film is locatedinside a peripheral edge of the antireflection film.

In one preferred embodiment, the step of supplying theadhesion-improving fluid includes the steps of: holding the substratehorizontally on a rotary stage; accommodating the peripheral edgeportion of the substrate held on the rotary stage in a space defined bya generally bracket-shaped nozzle body; rotating the substrate about avertical axis by the rotary stage; and supplying the adhesion-improvingfluid from nozzles provided in the nozzle body to the peripheral edgeportions of both front and back surfaces of the substrate.

In one preferred embodiment, the step of supplying theadhesion-improving fluid includes the steps of: disposing the substrateon a stage provided within a processing vessel; supplying a gas as theadhesion-improving fluid to the peripheral edge portion of the frontsurface of the substrate disposed on the stage; and exhausting aninterior of the processing vessel. in this case, in one preferred mode,the stage is shaped and sized such that the peripheral edge portion ofthe substrate projects outward from the stage when the substrate isdisposed on the stage, and wherein, in the step of supplying theadhesion-improving fluid, a gas as the adhesion-improving fluid issupplied also to a peripheral edge portion of a back surface of thesubstrate. Preferably, the step of exhausting the interior of theprocessing vessel exhausts the gas supplied onto the substrate so thatthe supplied gas flows toward outside of the substrate. In anotherpreferred embodiment, the step of supplying the adhesion-improving fluidis performed with a purge gas being supplied to a center portion of thefront surface of the substrate disposed on the stage and with a flow ofthe purge gas flowing toward the outside of the substrate being formed.

According to a third aspect of the present invention, there is provideda computer-readable storage medium storing a program, the program beingconfigured such that, when the program is executed by a control computerconnected to the foregoing coating and developing apparatus, the controlcomputer controls the coating and developing apparatus so as to executethe foregoing method.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic plan view showing a coating and developingapparatus in one embodiment of the present invention together with animmersion exposure apparatus connected thereto.

FIG. 2 is a schematic perspective view of the coating and developingapparatus shown in FIG. 1.

FIG. 3 is a schematic side view in vertical cross section of a resistcoating unit provided in the coating and developing apparatus shown inFIG. 1.

FIG. 4 is a schematic plan view of the resist coating unit shown in FIG.3.

FIG. 5 is a schematic side view in vertical cross section of aprotective film forming unit provided in the coating and developingapparatus shown in FIG. 1.

FIG. 6 is a schematic plan view of the protective film forming unitshown in FIG. 5.

FIG. 7 is a schematic vertical sectional view of an adhesion-improvingprocessor incorporated into the protective film forming unit shown inFIG. 5.

FIG. 8 is an explanatory diagram illustrating formation of a resist filmon an antireflection film.

FIG. 9 is an explanatory diagram showing an adhesion-improving step anda protective film forming step.

FIG. 10 is a flow chart showing a series of steps carried out by thecoating and developing apparatus shown in FIG. 1.

FIG. 11 is a schematic vertical cross-sectional view showing theconfiguration of an adhesion-improving processor, i.e., anadhesion-improving process unit, configured as an independent unit.

FIG. 12 is an explanatory diagram showing an air flow during processperformed in the adhesion-improving process unit shown in FIG. 11.

FIG. 13 shows diagrams illustrating a test for confirming the effect ofthe present invention and the results thereof.

FIG. 14 is a schematic sectional view illustrating an immersion exposureprocess.

FIG. 15 is a schematic plan view illustrating the immersion exposureprocess.

FIG. 16 is a diagram illustrating a peeling effect which may occur inthe immersion exposure process.

DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to FIGS. 1 and 2, a description will be given brieflyabout an entire configuration of a coating, exposing and developingsystem composed of a coating and developing apparatus in one embodimentof the present invention and an immersion exposure apparatus connectedthereto. In the following description, for simplification ofexplanation, X-axis positive direction, X-axis negative direction,Y-axis positive direction, and Y-axis negative direction, in FIG. 1,will be designated “front,” “rear,” “right,” and “left,” respectively. Acarrier block B1 is provided with: a carrier station 20 having mountportions 20 a, to and from which carriers C1 each containing, forexample, thirteen substrates such as wafers, in a sealed state aretransferred; apertures formed in a wall in front of the carrier station20 and respectively provided with shutters 21; and a wafer conveyer A1for taking out wafers W from the carriers C1 through the apertures. Thewafers W, which are loaded to the carrier station 20 while beingcontained in each carrier C1, are formed of silicon. As described in theforegoing “BACKGROUND ART”, the peripheral edge area of the frontsurface of each wafer W is not covered with a thin film, and thussilicon is exposed.

A process block B2 surrounded with a housing 22 is connected to a frontside of the carrier block B1. Provided in the process block B2 are unitstacks U1, U2 and U3 each including a heating/cooling unit,liquid-processing unit stacks U4 and U5, and main conveyers A2 and A3for transferring wafers W between units. The main conveyers A2 and A3are disposed respectively within spaces surrounded by partition walls23, which includes walls of the unit stacks (U1, U2; U2, U3) positionedon the front and rear sides of the main conveyers, walls of theliquid-processing unit stacks (U4; U5) positioned on the right sidethereof and walls positioned on the left side thereof. Reference numeral24 denotes temperature/humidity adjusting units each provided with atemperature adjusting device for adjusting temperatures of processingsolutions used in respective units and a duct of temperature/humidityadjustment.

As shown in FIG. 2, the liquid-processing unit stack U4 is constitutedby stacking, on a chemical-containing part containing chemicals such asa resist solution and an antireflection film forming solution: oneprotective film forming unit (ITC) 28 that applies a coating solution toform a protective film; two resist coating units (COT) 27 that apply aresist solution to form a resist film; and two antireflection filmforming units (BARC) 26 that apply a coating solution to form anantireflection film, in that order from below. The protective filmforming unit (ITC) 28 applies a coating solution containing awater-repellent organic material to the entire front surface of a waferW having thereon a resist film to form a water-repellent protective filmfor preventing a liquid from penetrating into the resist film duringimmersion exposure. The configuration of the protective film formingunit 28 and that of the resist film coating unit 27 will be described indetail later.

The liquid-processing unit stack U5 is constituted by stacking, on achemical-containing part containing chemicals such as a developingsolution, three developing units (DEV) 2A and two water-repellantprotective film removing units (ITR) 29 for removing the water-repellentprotective film in that order from below.

Each of the unit stacks U1, U2 and U3 are constituted by stacking, atmultiple (e.g., 10) levels, various units that perform pre-treatmentsand post-treatments for the liquid treatments performed by theliquid-processing unit stacks U4 and U5. The unit stacks U1, U2 and U3include a hydrophobizing unit that hydrophobize the entire front surfaceof a wafer W before formation of a resist film, a heating unit (PAB)that heats (bakes) the wafer W, and a cooling unit that cools the waferW. A transfer unit (TRS) for transferring a wafer W between the carrierblock B1 and the process block B2 is installed in the unit stack U1, anda transfer unit (TRS) for transferring a wafer W between the processblock B2 and an interface block B3 is installed in the unit stack U3.

In front of the unit stack U3, an exposure apparatus B4 is connected tothe process block B2 through the interface block B3. The interface blockB3 is made up of a first transfer chamber 3A and a second transferchamber 3B which are arranged anteroposteriorly between the processblock B2 and the exposure apparatus B4. A first transfer arm 31A and asecond transfer arm 31B, which are substrate conveyers, are provided inthe transfer chambers 3A and 3B, respectively. A unit stack U6 and abuffer cassette CO are provided in the first transfer chamber 3A. Theunit stack U6 is constituted by vertically stacking: a transfer stage(TRS) that mediates transferring of a wafer W between the first andsecond transfer arms 31A, 31B; and plural units including a heating unit(PEB) that heats a wafer W having been subjected to an exposure processand a high precision temperature adjusting unit having a cooling plate.

Provided in the second transfer chamber 3B is a cleaning unit (RD) forcleaning the front surface of a wafer W to remove water dropletsadhering to the water W in immersion exposure. The exposure apparatus B4is provided with a stage 40A that receives a wafer W from the interfaceblock B3 and a stage 40B that delivers an exposed wafer W to theinterface block B3.

The coating and developing apparatus is provided with a controller 100comprising a computer. Stored in the computer is a control program,which is configured so that operations of the coating and developingapparatus (described later), such as adjustment of the temperature of awafer W in the heating and cooling units, various film forming processesfor a wafer W, hydrophobizing process for a wafer W, and transferring ofa wafer W between the units, are carried out according to apredetermined process recipe. Upon execution of the control programstored in a program storage part, the computer, i.e., the controller 100sends instructions to various functional elements, including variousunits and conveyers, to control the operation of the coating anddeveloping apparatus. The control program can be stored in a hard diskdrive which is a storage medium provided fixedly in the computer.Alternatively, the control program may be stored in a removable storagemedium such as a compact disc, a magnet optical disc or a memory card,and may be executed by being read with a reader provided in thecomputer.

Next, with reference to FIGS. 3 and 4, the configuration of a resistcoating unit (COT) 27 will be described in detail. The coating unit 27is provided with a housing 50, i.e., a processing vessel. A transferport 51 for the wafer W is formed in a side wall, facing the mainconveyer A2, of the housing 50. The transfer port 51 can be opened andclosed with a shutter 52 installed in the same port. Disposed in theinterior of the housing 50A is a stage 53 is for placing a wafer Wthereon. The stage 53 is constituted as a vacuum chuck that sucks thecentral part of the back surface of a wafer W to hold it horizontally.The stage 53 is connected to a driver 53 b through a shaft 53 a. Thedriver 53 b can raise and lower the stage 53 and can rotate the stage 53about a vertical axis, thereby spin coating of a resist solution(described later) and transferring of a wafer W to and from the mainconveyer A2 are possible.

A cup 54 having an open upper end is disposed so as to surround theperipheral edge of the wafer W held on the stage 53. An upper endportion of the circumferential wall of the cup 54 is inclined inwards.Provided at the bottom of the cup 54 is a fluid recovery part 55extending circumferentially throughout the whole circumference of thecup. The fluid recovery part 55 is partitioned into an outer region andan inner region. A drain port 56 for draining the recovered resistsolution is formed in the bottom of the outer region. Two exhaust ports57 and 58 are formed in the bottom of the inner region. Gas in the cup54 is discharged at a predetermined flow rate through the exhaust ports57 and 58, whereby the resist solution scattered due to rotation of thewafer W is drawn into the fluid recovery part 55 and is discharged fromthe drain port 56.

Reference numeral 61 denotes a resist solution supply nozzle forsupplying the resist solution to the wafer W. One end of a resistsolution supply pipe 62 is connected to the resist solution supplynozzle 61, while the other end of the resist solution supply pipe 62 isconnected through a valve V1 to a resist solution supply source 63 whichstores the resist solution. One end of an arm 64 which supports theresist solution supply nozzle 61 is connected to the resist solutionsupply nozzle 61, while the other end of the arm 64 is connected to adriver 65. The driver 65 is slidable along a guide rail 66 which is laidhorizontally in the longitudinal direction of the housing 50.

An area, outside the cup 54, on the side opposite to the transfer port51 in the housing 50 is a stand-by area of the resist solution supplynozzle 61. During transfer of a wafer W between the main conveyer A2 andthe stage 53, the supply nozzle 61 stands by in the stand-by area. Whena wafer W is held on the stage 53, the resist solution supply nozzle 61moves to a position above the central part of the wafer W according tothe movement of the driver 65. Thereafter, the valve V1 is opened, sothat the resist solution flows at a predetermined flow rate into thesupply pipe 62 from the resist solution supply source 63 and is suppliedfrom the supply nozzle 61 to the central part of the wafer W.

Reference numeral 71 denotes an edge rinse nozzle (a first peripheraledge cleaner) that supplies a solvent to the peripheral edge portion ofa wafer W on which a resist film has been formed. One end of a solventsupply pipe 72 is connected to the edge rinse nozzle 71, while the otherend of the supply pipe 72 is connected through a valve V2 to a solventsupply source 73 which stores a solvent for a resist, e.g., thinner. Oneend of an arm 74 for supporting the nozzle 71 is connected to the edgerinse nozzle 71, while the other end of the arm 74 is connected to adriver 75. The driver 75 is adapted for rotation about a vertical axis.The edge rinse nozzle 71 moves from a stand-by area outside the cup 54to a processing position above the peripheral edge of the wafer W,according to the rotation of the driver 75.

When the edge rinse nozzle 71 moves to a position above the peripheraledge portion of the wafer W, the valve V2 is opened, so that the solventflows at a predetermined flow rate into the supply pipe 72 from thesolvent supply pipe 73, and is supplied from the edge rinse nozzle 71 tothe peripheral edge portion of the wafer W being rotated by the stage53. As a result, the resist film in the peripheral edge portion of thewafer W is removed such that the peripheral edge of the resist film ispositioned inside the peripheral edge of the antireflection filmunderlying the resist film. Note that, after formation of theantireflection film and before being conveyed to the resist coating unit(COT) 27, the wafer W is conveyed to a heating unit in the unit stacksU1 to U3 and is subjected to heat treatment, whereby the antireflectionfilm is baked to be hardened. Thus, the antireflection film is solvedlittle by the solvent supplied from the edge rinse nozzle 71.

In FIG. 4, the resist solution supply nozzle 61 and the edge rinsenozzle 71 positioned in respective stand-by areas are indicated by solidlines, while the resist solution supply nozzle 61 and the edge rinsenozzle 71 positioned in respective processing positions (positions forprocessing a wafer W) are indicated by two-dot chain lines.

As shown in FIG. 3, a filter 76 for removing particles is disposed in anupper portion in the housing 50. A vent chamber 77, which is apartitioned space, is formed in an upper portion of the filter 76. Oneend of a gas supply pipe 78 opend into the vent chamber 77, while theother end of the gas supply pipe 78 is connected to an N₂ gas supplysource 79 storing N₂ gas, for example. While the wafer W is loaded intothe housing 50 and a resist film forming process is carried out, a valveV3 is opened so that N₂ gas supplied from the gas supply source 79 tothe vent chamber 77 flows downwardly into the housing 50.

The antireflection film forming units 26, the protective film removingunits 29 and the developing units 2A included in the unit stacks U4 andU5 have the same configuration as that of the resist coating unit 27except that they are different in point of chemicals supplied to thewafer W. For example, in each antireflection film forming unit 26, thereare provided: a coating solution supply nozzle, for supplying a coatingsolution to form an antireflection film, having the same configurationas the resist solution supply nozzle 61; and an edge rinse nozzle (asecond peripheral edge cleaner) having the same configuration as theedge rinse nozzle 71. The edge rinse nozzle in the antireflection filmforming unit 26 supplies a solvent to the peripheral edge portion of thewafer W to remove the antireflection film present in the peripheral edgeportion.

Next, the configuration of the protective film forming unit 28 will bedescribed with reference to FIGS. 5 and 6. The protective film formingunit 28 has almost the same configuration as the resist coating unit 27.Therefore, different points from the coating unit 27 will mainly bedescribed. In FIGS. 5 and 6, component members of the protective filmforming unit 28 corresponding to the component members of the resistcoating unit 27 shown in FIGS. 3 and 4 are designated by the samereference numerals as those of the resist coating unit 27. The supplynozzle 61 in the protective film forming unit 28 supplies a coatingsolution for forming the protective film to the wafer W. In theprotective film forming unit 28, an area, outside the cup 54, on thetransfer port 51 side in the housing 50 serves as a stand-by area of thesupply nozzle 61.

Disposed in the protective film forming unit 28 is an adhesion-improvingprocessor 8 for improving the adhesion between a wafer W and theprotective film. The adhesion-improving processor 8 will now bedescribed with reference to FIG. 7. The adhesion-improving processor hasan adhesion-improving fluid feeder. The adhesion-improving fluid feederhas a nozzle body 81 of a bracket shape (a shape of a rectangle havingone opened side or a laterally-facing U shape) in side view. The nozzlebody 81 has an upper side portion 81 a, a lower side portion 81 b and alateral side portion 81 c.

A large number of gas supply ports 82 a and 82 b serving as a gas supplyportion are formed at intervals in the lower surface of the upper sideportion 81 a and the upper surface of the lower side portion 81 b,respectively. The gas supply ports 82 a and 82 b supply HMDS(hexamethylenedisilazane) gas to the peripheral edge portions of both ofthe front surface and the back surface of the wafer W when the nozzlebody 81 moves to the wafer processing position, which will be describedlater. Consequently, in the peripheral edge portion of the wafer frontsurface, an exposed surface exposed due to removal of the resist filmand the antireflection film is rendered hydrophobic by the HMDS gas toimprove the adhesion of the subsequently-formed protective film to theexposed surface. That is, the upper side portion 81 a provided thereinwith the gas supply port 82 a acts as a first fluid supply nozzle of theadhesion-improving processor, while the lower side portion 81 b providedtherein with the gas supply port 82 b acts as a second fluid supplynozzle of the adhesion-improving processor.

The gas supply ports 82 a and 82 b are in communication with gas flowpaths 83 a and 83 b, respectively, which are formed in the upper sideportion 81 a and the lower side portion 81 b. The gas flow paths 83 aand 83 b extend up to gas inlet ports 84 a and 84 b which are formedabove the upper side portion 81 a and below the lower side portion 81 b,respectively. One ends of supply pipes 85 a and 85 b are connected tothe gas inlet ports 84 a and 84 b, respectively. The other ends of thegas supply pipes 85 a and 85 b are respectively connected through valvesV4 a and V4 b to HMDS gas supply sources 86 a and 86 b in which HMDS gasis stored.

In the lateral side portion 81 c of the nozzle body 81, a suction port86, or a suction nozzle, is formed at the center portion of the surfacefacing the wafer W. One end of a suction pipe 87 is connected to thesuction port 86. The other end of the suction pipe 87 is connected to asuction mechanism 87 a, e.g., a vacuum pump, through a valve V5. Asnoted previously, the suction port 86 suctions the space surrounded bythe upper, lower and lateral side portions 81 a, 81 b, 81 c of thenozzle body 1 when HMDS gas is discharged from the gas supply ports 82 aand 82 b. As a result, surplus HMDS gas supplied from the gas supplyports 82 a and 82 b and NH₃ (ammonia) gas generated through reaction ofHMDS gas with water present on the surface of the wafer W, are suckedand removed from the suction port 86. Arrows shown in FIG. 7 representgas flows in the space surrounded by the side portions 81 a to 81 cduring process of the wafer W.

One end of an arm 88 which supports the nozzle body 81 is connected to apart, above the gas inlet port 84 a, of the upper side portion 81 a. Theother end of the arm 88 is connected to a driver 89 which is slidable onthe guide rail 66. An area, outside the cup 54, on the side opposite totransfer port 51 in the housing 50 of the protective film forming unit28 serves as a stand-by region of the nozzle body 81. In FIG. 5, thenozzle body 81 positioned in the stand-by area is indicated by solidlines. During transfer of the wafer W between the stage 53 b raised bythe driver 53 b and the main conveyer A2, the nozzle body 81 stands byin the aforesaid stand-by area. After the stage 53 receives the wafer W,the nozzle body 81 moves to the processing position indicated by two-dotchain lines in FIG. 5 according to movement of the driver 89. At thistime, the peripheral edge portion of the wafer W is positioned betweenthe upper side portion 81 a and the lower side portion 81 b.

Next, the operation of the processing system including the foregoingcoating and developing apparatus will be described with reference alsoto FIGS. 8 to 10. First, when a carrier C1 containing wafers W which hasbeen conveyed from the exterior of the processing system is put on acarrier portion 20 a, the shutter 21 opens, a lid of the carrier C1 isremoved, and a wafer W is taken out by the wafer conveyer A1. The waferW thus taken out is conveyed to the main conveyer A2 through thetransfer unit (TRS) included in the unit stack U1.

The main conveyer A2 transfers the wafer W to the antireflection filmforming unit 26, in which a coating solution for forming anantireflection film is supplied to the entire front surface of the waferfrom the supply nozzle to form an antireflection film 101. Thereafter, asolvent is supplied from the edge rinse nozzle to the peripheral edgeportion of the wafer W, whereby the antireflection film 101 present inthe peripheral edge portion is removed. Then, the wafer W is transferredto the main conveyer A2, the heating unit included in either the unitstack U1 or U2, the main conveyer A2, the cooling unit included ineither the unit stack U1 or U2, the hydrophobizing unit included ineither the unit stack U1 or U2, the cooling unit included in either theunit stack U1 or U2 and the main conveyer A2, in that order.Subsequently, the wafer W is transferred to a resist coating unit (COT)27 by the main conveyer A2 and the central part of the back surface ofthe wafer W is chucked to be held by the raised stage 53. Uponwithdrawal of the main conveyer A2 from the resist coating unit 27, thestage 53 descends while holding the wafer W. After the wafer W isaccommodated in the cup 54, the resist solution supply nozzle 61 movesfrom the stand-by area outside the cup 54 to the processing positionabove the central part of the wafer W.

Subsequently, the wafer W is rotated by the driver 53 b at apredetermined speed about a vertical axis via the stage 53, and thevalve V1 is opened to supply the resist solution from the resistsolution supply nozzle 61 to the wafer W. By virtue of centrifugalforce, the resist solution thus supplied spreads from the central partof the wafer W to the peripheral edge portion of the same. That is, theresist solution is applied to the wafer W by a spin coating method. Theresist solution is supplied for a predetermined time, and thereafter thesupply of the resist solution is stopped. After that, the rotation ofthe wafer W is continued for a while, during which the solvent containedin the resist solution volatilizes and a resist film 102 is formed onthe wafer W so as to entirely cover the antireflection film 101, asshown in FIG. 8( a).

Next, the edge rinse nozzle 71 moves by the driver 75 to a positionabove the peripheral edge portion of the wafer W from its stand-by area,and a solvent is supplied from the rinse nozzle 71 to the peripheraledge portion of the rotating wafer W, as shown in FIG. 8( b), wherebythe resist film 102 in the peripheral edge portion is removed. As aresult, as shown in FIG. 8( c), the peripheral edge portion of the waferW is exposed, and the peripheral edge of the resist film 102 ispositioned inside the peripheral edge of the antireflection film 101(step S1).

Upon completion of the removal of the resist film 102 in the peripheraledge portion, the supply of the solvent is stopped and the rotation ofthe wafer W is stopped, and the resist solution supply nozzle 61 and therinsing nozzle 71 are withdrawn to the respective stand-by areas.Thereafter, the driver 53 b raises, via the stage 53, the wafer W to aposition outside of the cup 54 as indicated by chain dotted lines inFIG. 3. The main conveyer A2 enters the interior of the unit 27,receives the raised wafer W, and transfers the wafer W to the heatingunit (PAB) included in either the unit stack U1 or U2. In this heatingunit, the wafer W is subjected to a heating process at a predeterminedtemperature, whereby the solvent contained in the resist film 102 isvaporized to be removed (step S2).

After the heating process, the wafer W is taken out from the heatingunit (PAB) and is loaded into the cooling unit included in either theunit stack U1 or U2 by the main conveyer A2. Next, the main conveyer A2transfers the wafer W, which has been subjected to temperatureadjustment in the cooling unit, into the protective film forming unit28. Then, the stage 53 in the protective film forming unit 28 rises andchucks the central part of the back surface of the wafer W. Uponwithdrawal of the main conveyer A2 from the protective film forming unit28, the nozzle body 81 of the adhesion-improving processor 8 moves fromits stand-by area toward the wafer W and stops in its processingposition in which the peripheral edge portion of the wafer W ispositioned between the upper side portion 81 a and the lower sideportion 81 b of the nozzle body 81.

Subsequently, the drive section 53 b rotates, via the stage 53, thewafer W at a predetermined speed. The valves V4 a, V4 b and V5 areopened slightly after the start of rotation of the wafer W. Thereby,HMDS gas is supplied from the supply ports 82 a and 82 b of the nozzlebody 81 toward both the front surface and the back surface of theperipheral edge portion of the wafer W, and the space surrounded by theupper side portion 81 a, lower side portion 81 b and lateral sideportion 81 c of the nozzle body 81 is suctioned through the suction port86, whereby gas flow as indicated by arrows in FIG. 9( a) is formed inthe space. By being exposed to the gas flow, the area, which extendsfrom an exposed surface 104 of the peripheral edge portion of the frontsurface of the wafer W through the peripheral edge side face of thewafer W to the peripheral edge portion of the back surface of the waferW, is rendered hydrophobic, so that the adhesion of the area to theprotective film 103 is improved. At this time, surplus HMDS gas and NH₃gas, the latter being a reaction product between the HMDS gas and themoisture present on the wafer front surface, are suctioned through thesuction port 86 to be removed from space surrounded by thebracket-shaped nozzle body 81 (step S3).

When a predetermined time has elapsed after opening of the valves V4 a,V4 b and V5 so that the hydrophobizing process for the peripheral edgeportion of the wafer W is completed, these valves are closed and thesupply of HMDS gas from the supply ports 82 a and 82 b is stopped andthe suctioning through the suction port 86 is stopped. Thereafter, therotation of the stage 53 is stopped and the nozzle body 81 is withdrawnto its stand-by area. Then, the stage 53 descends so that the wafer W isaccommodated in the cup 54. Subsequently, the liquid supply nozzle 61for supplying a protective film forming material moves from the stand-byarea outside the cup 54 to the processing position above the centralpart of the wafer W.

After the liquid supply nozzle 61 moves to the processing position, thedriver 53 b rotates, through the stage 53, at a predetermined speedabout a vertical axis. Almost simultaneously with the start of rotationof the wafer W, the valve V1 is opened, so that a protective filmforming material 105 is supplied from the liquid supply nozzle 61 to thewafer W, and spreads from the central part of the wafer W to theperipheral edge portion due to centrifugal force, similar to the resistsolution described above, as shown in FIG. 9( b). After a predeterminedtime has elapsed from the supply of the protective film forming material105, the supply of the material 105 is stopped. The rotation of thewafer W is continued for a while, so that the solvent contained in theprotective film forming material 105 volatilizes whereby awater-repellent protective film 103 is formed on the entire surface ofthe wafer W, as shown in FIG. 9( c) (step S4).

After the formation of the protective film 103, the rotation of thewafer W is stopped and the supply nozzle 61 is withdrawn to its stand-byarea. Thereafter, the stage 53 rises while holding the wafer W anddelivers the wafer to the main conveyer A2 which has entered into theunit 28. The main conveyer A2 transfers the wafer W into the heatingunit included in either the unit stack U1 or U2, in which the wafer issubjected to a heating process at a predetermined temperature (step S5).

The wafer W having been subjected to the heating process is transferredto the main conveyer A2, the cooling unit included in either the unitstack U1 or U2, the main conveyer A3, the transfer unit (TRS) in theunit stack U3, the first transfer arm 31A in the interface block B3, thetransfer unit (TRS) in the unit stack U6, the second transfer arm 31Band the stage 40A in the exposure apparatus B4, in that order.Thereafter, as previously described in detail in the “BACKGROUND ART”,the wafer W is placed on an exposure stage (not shown) in the exposureapparatus B4 where it is subjected to immersion exposure process usingthe immersion exposure head 1 (see FIG. 14) (step S6).

The wafer having been subjected to the immersion exposure is put on thetransfer stage 40B in the exposure apparatus B4, and is conveyed intothe interface block B3 by the second transfer arm 31B, and then istransferred to a cleaning device (RD), the transfer stage (TRS) in theunit stack U6, the first transfer arm 31A and the heating unit (PEB) inthe unit stack U6, in that order. In the heating unit (PEB), heatingprocess is performed (step S7), whereby an acid generated from an acidgenerating component contained in the resist of the exposed portiondiffuses within the resist film. Under the effect of the acid, achemical reaction occurs in the resist component, whereby a positivetype resist becomes soluble in the developing solution, while a negativetype resist becomes insoluble in the developing solution.

After the heating process, the wafer W is taken out of the heating unit(PEB) by the first transfer arm 31A, and is transferred to thetemperature adjusting unit in the unit stack U6, the first transfer arm31A, the transfer stage (TRS) in the unit stack U3, the main conveyer A3and a protective film removing unit 29 in that order. In the protectivefilm removing unit 29, a protective film removing solution is suppliedto the wafer W, whereby the protective film 103 is removed from thewafer W (step S8). After the removal of the protective film 103, thewafer W is loaded into a developing unit 2A by the main conveyer A3. Inthe developing unit 2A, a developing solution is supplied to the frontsurface of the wafer W, and portions of the resist film 102, which issoluble in the developing solution, is dissolved, whereby a resist maskof a predetermined pattern is formed on the wafer front surface (stepS9). Thereafter, the wafer W is transferred to the main conveyer A3, theheating unit included in either the unit stack U2 or U3, the mainconveyer A3, the cooling unit included in either the unit stack U2 orU3, the main conveyer A2, the transfer unit (TRS) in the unit stack U1and the conveyer 1, in that order, and is returned to the originalcarrier C1 on the carrier portion 20 a by the conveyer A1.

The coating and developing apparatus of the foregoing embodiment isprovided with: the antireflection film forming units 26 that forms anantireflection film on the front surface of the wafer W; the resistcoating unit 27 that forms a resist film on the antireflection film, andthe protective film forming unit 28 that forms a protective film for theresist film formed of a water-repellent material on the whole frontsurface of the wafer W. Further, the protective film forming unit 28 isprovided with the adhesion-improving processor that supplies HMDS gas toan area including an exposed surface of silicon in the peripheral edgeportion of the wafer W which has been exposed by removing the resistfilm and the antireflection film by supplying solvents from the edgerinse nozzles 71 of the units 26 and 27, thereby making theaforementioned area hydrophobic to improve the adhesion of theprotective film to the exposed surface. Therefore, even when the wafer Wis under pressure of a liquid film which is formed on the wafer W by theimmersion exposure head 1 (see FIG. 14) when the wafer W is subjected toa immersion exposure process, peeling-off of the protective film fromthe exposed surface of the wafer W can be prevented. Thus, it ispossible to avoid development of defects in a pattern, which otherwisemay be caused by the fact that resist film contacts with pure waterforming the liquid film and is subjected to physical force of the purewafer to be peeled off from the substrate so that a normal developingprocess is obstructed. Moreover, it is possible to prevent the formationof particles derived from the peeled-off protective film and resistfilm, which would contaminate the interior of the exposure apparatus B4to cause defects in an exposure process of the wafer W, or would adhereto the wafer W to cause defects in such processes as a heating processand a developing process after exposure process.

The adhesion-improving processor 8 is provided with the bracket-shapednozzle body 81; the upper side portion 81 a and the lower side portion81 b of the nozzle body 81 are disposed so as to sandwich the peripheraledge portion of the wafer W; and suctioning is performed by the suctionport 86 formed in the lateral side portion 81 c of the nozzle body 81,while supplying HMDS gas from the gas supply ports 82 a and 82 b formedin the upper and lower side portions 81 a, 81 b to the area includingthe exposed surface of the wafer W. Therefore, it is possible to preventHMDS gas from adhering to the surface of the resist film and to preventHMDS from being deposited thereon. Consequently, it is possible toprevent any defects in the exposure process due to deposited HMDS. Inaddition, the consumption of HMDS gas is suppressed in comparison withthe case where HMDS gas is supplied to the whole surface of the wafer W,thus reducing the cost.

The stage 53, which is used for spreading the protective film formingmaterial 105 in the protective film forming unit 28 to the whole surfaceof the wafer W by spin coating, is used also as a rotary stage for thesupply of HMDS gas to the peripheral edge portion of the wafer W.Therefore the number of the stage in the unit 28 may be only one.Consequently, an increase in size of the unit 28 and that of the coatingand developing apparatus are avoided.

In the foregoing embodiment, the hydrophobizing process is performed bysupplying HMDS gas to the area including the exposed surface of thewafer W in order to enhance the adhesion between the wafer W and theprotective film 103. Alternatively, in the hydrophobizing process, a gasof methylsilane series compound such as isopropenoxytrimethylsilane maybe supplied. The hydrophobizing process may be carried out by applying aliquid containing a methylsilane series compound and under the situationwhere a puddle of the liquid is formed on the exposed surface.

The effect according to the present invention can be achieved if theforegoing HMDS gas is supplied to the exposed surface of silicon in theperipheral edge portion of the wafer W during the period after removalof the peripheral edge portion of the resist film and before formationof the protective film for the resist film. Thus, in a series of processsteps for the wafer W performed by the foregoing coating and developingapparatus, the antireflection film need not be formed on the wafer W,and a film of another material may be formed between the antireflectionfilm and the resist film.

The adhesion-improving processor 8 which performs the hydrophobizingprocess as in the foregoing embodiment is not limited to the oneinstalled within the protective film forming unit 28, but may beconstituted as one independent liquid-processing unit which constitutesthe liquid-processing unit stack U4 or U5. FIG. 11 shows an example ofsuch an adhesion improving unit. Like the coating units 27 describedabove, this adhesion improving unit 9 is provided with a housing 50, atransfer port 51 and a shutter 52. A sealed vessel 9A composed of a lid91 and a vessel body 92 is disposed in the interior of the housing 50. Atable 93 for the wafer W, or a non-rotary stage, is disposed in thevessel body 92. Vertically-movable support pins (not shown) are providedin the table 93. A wafer W is transferred between the foregoing mainconveyers A2, A3 and the table 93 via the support pins.

An exhaust path 94 is formed in the sealed vessel 9A so as to surroundthe table 93. One end of an exhaust pipe 94 a which is for exhaustingthe interior of the sealed vessel 9A through the exhaust path 94 isconnected to the exhaust path 94, while the other end of the exhaustpipe 94 a is connected to suction means 94 through a valve V6.

An N₂ gas feeder 95, or a second gas feeder, is disposed in the centralportion of the lid 91 so as to face the central portion of the wafer Wplaced on the table 93. An HMDS gas feeder 96, or a first gas feeder, isdisposed in the peripheral edge portion of the lid 91 so as to face theperipheral edge portion of the wafer W and surround the N₂ gas feeder95. The N₂ gas feeder 95 is connected through a gas supply pipe 95 a toa gas supply source 95 b storing N₂ gas. As will be described later, theN₂ gas is a purge gas which is supplied for removing surplus HMDS gasfrom the space near the peripheral edge portion of the wafer W in orderto prevent the adhesion of the surplus HMDS gas to the resist film. Gasflow generated by the supply of the N₂ gas prevents the HMDS gasentering into the central portion of the wafer W. The HMDS gas feeder 96is connected through a gas supply pipe 96 a to a gas supply source 96 bstoring HMDS gas. Symbols V7 and V8 denote valves disposed in the gassupply pipes 95 a and 96 a, respectively.

In the adhesion improving unit 9, the lid 91 rises and the wafer W isput on the table 93 via the foregoing support pins. After the wafer W isput on the table 93, the lid 91 closes and HMDS gas is supplied from theHMDS gas feeder 96 to the peripheral edge portion of the wafer W, whileN₂ gas is supplied from the N₂ gas feeder 95 to the central portion ofthe wafer W. In this case, the interior of the sealed vessel 9A isexhausted through the exhaust pipe 94 a. FIG. 12 shows gas flow in thesealed vessel 9A in this case, in which solid lines represent the flowof HMDS gas and chain lines represent the flow of N₂ gas. As shown inFIG. 12, HMDS gas is supplied to the exposed surface of the wafer W fromwhich both the resist film and the antireflection film have been removedso as to render the exposed surface hydrophobic, and the HMDS gas isthen sucked to the outside of the wafer W by the exhaust pipe 94 a. TheN₂ gas, after being supplied to the central portion of the wafer W, goestoward the peripheral edge portion of the wafer W along the wafersurface, flows outwardly while entraining the surplus HMDS gas presentin the space near the peripheral edge portion of the wafer, and flowsinto the exhaust pipe 94 a through the exhaust path 94 together withHMDS gas to be discharged from the interior of the sealed vessel 9A.

In a case where the adhesion improving unit 9 is installed in a coatingand developing apparatus, the foregoing effect can also be obtained.However, in a case where the adhesion-improving processor 8 is installedin the protective film forming unit 28, increment in the number ofprocessing units in the coating and developing apparatus is suppressed,and complex motions of the main conveyers A2 and A3 for transferring awafer W between the processing units can be avoided and thus acomplicated transfer program can be avoided.

A description will now be given about a test conducted to confirm theeffect of the present invention. Plural wafers W of silicon wereprepared. No thin film was formed on the surfaces of the prepared wafersW. HMDS gas was supplied to the surface of the peripheral edge portionincluding a beveled portion of one wafer W to perform a hydrophobizingprocess, while the hydrophobizing process using HMDS gas was notperformed for the other wafer W.

A processing solution for a protective film for a resist film wasapplied to the whole surface of the wafer W subjected to thehydrophobizing process and the whole surface of the wafer W notsubjected to the hydrophobizing process, using a coating unit asdescribed in the foregoing embodiment, to form an organic film 111 onthe whole surface of each wafer W. Then, as shown in FIG. 13( b), thewafers W having the organic film 111 formed thereon were held in avertical attitude; and a nozzle 112 was disposed above each wafer W andpure water was vertically and downwardly discharged from the nozzle 112toward the wafer W. The discharge flow rate and the discharge time ofpure water were set to 4.1 L/min and 60 sec, respectively. At this time,the flow velocity of pure water was about 500 mm/sec.

Thereafter, the state of the beveled portion, supplied with the purewater, of each wafer W was observed. As shown in FIG. 13( c), in thewafer W whose peripheral edge portion was supplied with HMDS gas beforeformation of the organic film 111, peeling-off of the organic film 111was not observed. However, in the wafer W to which HMDS gas was notsupplied, peeling-off of the organic film 111 was observed. Thus, it wasproved that the adhesion between the silicon surface of wafer and theorganic film formed thereon could be enhanced by supplying HMDS gas tothe peripheral edge portion of the wafer to render the peripheral edgeportion hydrophobic.

The invention claimed is:
 1. A method of forming at least a resist film and a water-repellent protective film on a substrate to be subjected to immersion exposure, said method comprising the steps of: applying a resist solution to a front surface of the substrate thereby forming a resist film; removing the resist film existing in a peripheral edge portion of the front surface of the substrate by using a solvent; supplying an exposed surface, exposed due to removal of the resist film, with an adhesion-improving fluid for improving adhesion of the protective film to the exposed surface; and thereafter applying a coating solution for forming the protective film to the front surface of the substrate thereby forming the protective film.
 2. The method according to claim 1, wherein, in the step of supplying the adhesion-improving fluid, the adhesion-improving fluid is supplied also to a peripheral edge portion of a back surface of the substrate.
 3. The method according to claim 1, further comprising the steps of: supplying, before the step of applying the resist solution, a coating solution for forming an antireflection film to the front surface of the substrate thereby forming the antireflection film; and removing the antireflection film existing in the peripheral edge portion of the front surface of the substrate by using a solvent, wherein, after the resist film removing step, a peripheral edge of the resist film is located inside a peripheral edge of the antireflection film.
 4. The method according to claim 1, wherein the step of supplying the adhesion-improving fluid includes the steps of: holding the substrate horizontally on a rotary stage; accommodating the peripheral edge portion of the substrate held on the rotary stage in a space defined by a generally bracket-shaped nozzle body; rotating the substrate about a vertical axis by the rotary stage; and supplying the adhesion-improving fluid from nozzles provided in the nozzle body to the peripheral edge portions of both front and back surfaces of the substrate.
 5. The method according to claim 1, wherein the step of supplying the adhesion-improving fluid includes the steps of: disposing the substrate on a stage provided within a processing vessel; supplying a gas as the adhesion-improving fluid to the peripheral edge portion of the front surface of the substrate disposed on the stage; and exhausting an interior of the processing vessel.
 6. The method according to claim 5, wherein the stage is shaped and sized such that the peripheral edge portion of the substrate projects outward from the stage when the substrate is disposed on the stage, and wherein, in the step of supplying the adhesion-improving fluid, a gas as the adhesion-improving fluid is supplied also to a peripheral edge portion of a back surface of the substrate.
 7. The method according to claim 5, wherein the step of exhausting the interior of the processing vessel exhausts the gas supplied onto the substrate so that the supplied gas flows toward outside of the substrate.
 8. The method according to claim 5, wherein the step of supplying the adhesion-improving fluid is performed with a purge gas being supplied to a center portion of the front surface of the substrate disposed on the stage and with a flow of the purge gas flowing toward the outside of the substrate being formed.
 9. The method according to claim 1, wherein the adhesion-improving fluid is hexamethyldisilazane.
 10. A computer-readable storage medium storing a program, the program being configured such that, when the program is executed by a control computer connected to a coating and developing apparatus, the control computer controls the coating and developing apparatus so as to execute the method according to claim
 1. 11. The method according to claim 1, wherein the step of supplying the adhesion-improving fluid to the exposed surface is performed in such a manner that a surface of the resist film remaining in a central portion of the front surface of the substrate is not supplied with the adhesion-improving fluid. 